1. Field of the Invention
The invention relates to electrical power systems and, more particularly, to power center systems having electrical receptacles, voice/data communication ports and/or similar devices mountable in furniture assemblies and the like.
2. Description of Related Art
The use of computers, sophisticated telecommunications equipment and other electronic devices is continuing to rapidly increase in commercial, industrial and other office environments. As a result, the importance of efficiently supplying power throughout these environments is also increasing. Historically, one problem common to the use of electrical power and communications equipment is the positioning of electrical power outlet communication ports, such as conventional RS-232 voice/data interface connectors. Positioning of these devices is important with respect to both convenience and cost efficiency. Electrical receptacles and communication ports for supplying power and communication signals to various types of devices (lighting, computers, etc.) must be located in accessible positions for all types of use.
However, the cost of electrical materials rapidly increases as the number of power source receptacles and associated equipment is increased. In addition, and perhaps more importantly, the conventional design of single- or double-unit receptacles (for both electrical power and communications) within walls or floor surfaces, which are often a substantial distance from the devices to be powered or with which to communicate, cause unsightly and sometimes dangerous arrays, and may result in entanglements of the electrical cords and communications wires connected to the devices.
To overcome the problems associated with efficiency and convenience of electrical and communications outlet design, it is not uncommon to employ multiple receptacle raceways having a number of receptacles or ports with a common power source cord or communications cable plugged into a utility or commercial communications company's outlet. Again, however, the raceways result in unsightly and entangled arrays of electrical cords and communication lines. In addition, such raceways are often located on floor surfaces and are not particularly convenient.
It is also known to employ electrical receptacles and communications ports (commonly known as "data ports") rigidly and directly mounted to various types of furniture, such as book shelves and desks. These receptacles may be mounted at a location substantially above the floor surface, and allow the user to interconnect electrical and communications devices nearer their location of use, thereby avoiding the necessity of running device cords and cables a substantial distance. However, rigidly secured receptacles and data ports must be mounted in a manner so that the user can readily insert device plugs and corresponding communication port connectors. Accordingly, these receptacles and data ports are typically in a fairly "open" location, and the device cords again may prove to be unsightly and space consuming. If, alternatively, the receptacles are somewhat hidden from view, they can be difficult to access.
A system employing covered receptacles mounted within a work station is disclosed in Propst, U.S. Pat. No. 4,372,629 issued Feb. 8, 1983. The Propst et al. arrangement includes a desk top having a rear cover hinged to a vertical back panel. Receptacles are mounted to the lower portion of the cover and bristles extend horizontally from the cover to an edge of the desk top when the cover is closed. When the cover is open, the user can plug in the cord of a desired electrical device and close the cover, with the cord then extending through the bristles.
One relatively substantial advance over the prior art, relating to the mounting of electrical receptacles in a retractable manner in work surfaces and the like, is shown in the commonly owned Byrne, U.S. Pat. No. 4,551,577 issued Nov. 5, 1985. In the Byrne patent, a retractable power center includes a rectangular housing formed in the work surface, with a clamping arrangement to secure the housing to the work surface. A lower extrusion is connected to a lower portion of the housing, and a movable power carriage mounts receptacles. A catch assembly releasably maintains the carriage in a closed, retracted position. In response to manual activation, the catch assembly is released and springs tensioned between the carriage and the extrusion exert forces so as to extend the carriage upward into an extended open position. In the open position, the user can energize desired electrical devices from the receptacles, and then lower the carriage into the releasably secured, retracted position.
Although the foregoing Byrne patent represents a substantial advance with respect to retractable power centers mounted on work surfaces and the like, it can also be advantageous to employ a retractable power center having a relatively more simple construction. That is, the use of spring or similar arrangements can sometimes result in additional repair and maintenance costs. Further, the use of a relatively long extrusion and the spring assemblies can also result in higher initial costs.
In this regard, a further advance over the prior art was achieved with the commonly owned Byrne, U.S. Pat. No. 4,747,788 issued May 31, 1988. In this patent, a retractable power center is disclosed which is manually operable. The power center includes a stationary upper housing received within a slot formed within a work surface, and a clamping arrangement to secure the housing to the work surface. A manually movable and vertically slidable power carriage is utilized to mount the electrical receptacles. In response to manually exerted forces, the carriage can be extended vertically upward into an open position. Small bosses extend laterally from the sides of the carriage to provide a means to support the carriage in its extended position, with the bosses resting in the top portion of the housing. Ledges are integrally formed on the lateral sides of the carriage near the bottom portions thereof, so as to prevent any additional movement of the carriage upwardly relative to the housing.
An example of a device having electrical receptacles, data ports and other types of communication outlets is disclosed in Brownlie et al., U.S. Pat. No. 4,984,982 issued Jan. 15, 1991. The Brownlie patent illustrates an access flooring module to be mounted in an opening provided in an access floor. The module is movable between open and closed positions, and recesses are provided so as to receive electrical components such as power sockets or signal sockets. Electrical isolation is provided between certain components. In an alternative embodiment a high tension cable and low tension cable are interconnected to the rear of a module. The high tension cable is secured through a hard wire bracket, with the low tension cable secured through a data bracket. Cable ties are utilized to secure the cables to the rear of the module.
A device comprising both electrical power and data service lines, and specifically directed to use in a work surface, is disclosed in Timmerman, U.S. Pat. No. 5,575,668 issued Nov. 19, 1996. In the Timmerman patent, a temporary power/data tap is provided for delivering both electrical power and data service to a work surface from a distant standard wall or floor mounted electrical receptacle and data port. The power/data tap is movable between retracted and extended positions. The Timmerman patent illustrates a temporary power/data tap comprising an enclosure assembly, power distribution assembly, at least one outlet enclosure and a power cord. The enclosure assembly comprises a box structure having a top opening with two side surfaces and two removable end surfaces. The side surfaces include spot welded nuts on their inside surfaces for mounting the enclosure assembly to a work surface. The inside surface of the side surfaces of the box structure include rivets intruding into non-conductor space and serving as positive stops for the outlet enclosure housed therein. The end surfaces can also have openings for receiving a strain relief bushing or an electrical connector.
Disposed inside the enclosure assembly is a power distribution assembly for receiving and distributing electrical power through the enclosure assembly to the outlet enclosure. The power distribution assembly is an I-shaped structure comprising a first junction box and a second junction box. Each of the junction boxes includes a recessed central area with two centrally located conduit holes manufactured thereon which are used to attach one end of a metallic rigid conduit and a metallic flexible conduit. Trade holes are also manufactured on the inside surface near the upper edge of each junction box, for engaging bullet catches located on lateral sides of each outlet enclosure for purposes of limiting the upper rotation of the outlet enclosure from the enclosure assembly.
During assembly, the power distribution assembly is disposed inside the enclosure assembly over a bottom surface so that a rigid conduit is parallel with the longitudinal axis of the enclosure assembly, with the junction boxes disposed on opposite sides thereof. This concept is shown in FIG. 5 of the Timmerman patent. Electrical power is delivered to the enclosure assembly from a standard receptacle by means of a power cord. The power cord extends through a bushing attached to the side surface of the box structure.
In the embodiment shown in FIGS. 1 and 2 of Timmerman, two outlet enclosures are placed through the top opening and disposed in a side-by-side manner inside the enclosure assembly. A hinge is disposed between the two outlet enclosures or between one outlet enclosure and the enclosure assembly, thereby enabling the outlet enclosures to freely pivot inside the enclosure assembly. Each outlet enclosure is made of sheet metal and comprises a cover and a box member divided by a partition into first and second compartments. The cover is connected along its back edge by a full length hinge to the top surface of the box member. A connecting rod is used to interconnect the hinge element on the cover with the hinge elements located on an adjacent outlet enclosure or on the enclosure assembly. The box member is divided into a first compartment used to house high voltage electrical connections, and a second compartment used to house low voltage electrical connections, such as data service line connections. Each end of the box member is fitted with a bullet cache which engage trade holes manufactured on the sides of the adjacent junction box to limit the upward rotation of the outlet enclosure. Manufactured on a front surface of the box member are cutouts for receiving the electrical power receptacle and the data port. Manufactured on the bottom surface of the box member directly under the first compartment is an opening which enables a flexible conduit to be attached to the box structure. Attached over a rear opening of the box member is a removable cover. The cover fully encloses the first compartment and partially cover the rear opening of the second compartment, thereby providing a means for the data service line to enter the second compartment.
To mount the temporary tap to a work surface, a suitable opening is manufactured on the work surface slightly larger than the box structure. Mounting brackets are utilized to attach the box structure to the work surface. In general, the Timmerman patent shows the concept of a power center pivotable between open and closed positions, with the power center having both an electrical receptacle and a data port mounted in separate and isolated compartments.